1. Field of the Invention
This invention relates to valves for regulating fluid flows and fluid pressures, and to gas turbine engine fuel control systems incorporating such valves.
2. Discussion of Prior Art
It is known to provide metering valves for fluids in which a control element is moved in response to variations in a servo-pressure, the servo-pressure being regulated by a valve which is energised by an electric force motor. It is a disadvantage of such known valves that failure of the force motor or its current supply may result in rapid change in the servo-pressure and consequent rapid movement of the valve control element away from its previously selected position. The present invention describes a metering valve arrangement in which this disadvantage is overcome.